The Resource Theory of Quantum States Out of Thermal Equilibrium

The ideas of thermodynamics have proved fruitful in the setting of quantum information theory, in particular the notion that when the allowed transformations of a system are restricted, certain states of the system become useful resources with which one can prepare previously inaccessible states. The theory of entanglement is perhaps the best-known and most well-understood resource theory in this sense. Here we return to the basic questions of thermodynamics using the formalism of resource theories developed in quantum information theory and show that the free energy of thermodynamics emerges naturally from the resource theory of energy-preserving transformations. Specifically, the free energy quantifies the amount of useful work which can be extracted from asymptotically-many copies of a quantum system when using only reversible energy-preserving transformations and a thermal bath at fixed temperature. The free energy also quantifies the rate at which resource states can be reversibly interconverted asymptotically, provided that a sublinear amount of coherent superposition over energy levels is available, a situation analogous to the sublinear amount of classical communication required for entanglement dilution.Comment: 4.5 pages main text, 12 pages appendix; v3: improvements to presentation of the main resul

Gravitational waves physics using Fermi coordinates: a new teaching perspective

The detection of gravitational waves is possible thanks to a multidisciplinary approach, involving different disciplines such as astrophysics, physics, engineering and quantum optics. Consequently, it is important today for teachers to introduce the basic features of gravitational waves science in the undergraduate curriculum. The usual approach to gravitational wave physics is based on the use of traceless and transverse coordinates, which do not have a direct physical meaning and, in a teaching perspective, may cause misconceptions. In this paper, using Fermi coordinates, which are simply related to observable quantities, we show that it is possible to introduce a gravitoelectromagnetic analogy that describes the action of gravitational waves on test masses in terms of electric-like and magnetic-like forces. We suggest that this approach could be more suitable when introducing the basic principles of gravitational waves physics to students.Comment: 20 pages, 5 figures, Accepted for publication in the American Journal of Physic

Spatial filtering of visible light in a spectrophotometric camera for artwork imaging

The preservation and reproduction of a still artwork needs the knowledge of its spectral reflectance, obtainable in laboratory by spectrophotometric scanners. This work proposes the design of a miniaturized spectrophotometric camera with spatial filtering of the light for measuring the spectral reflectance factor and the spectral radiance of the objects of a scene

Small dimensions portable instruments for in-situ multispectral imaging

The design of a compact spectrometer for analysis of artworks is presented. Its operation is based on the use of a variable transmission filter associated with an array detector. The instrument allows the measurement of the spectral reflectance factor and combines the acquisition of data in a continuous spectrum with the small dimension that is of primary importance for in-situ spectral imaging. Keywords: compact spectrometers, image spectrometry, optical filter

A portable Spectro-photo/radio-metric Camera with Spatial Filtering for VIS-NIR Imaging

This work proposes the design of a miniaturized spectrophoto/radio-metric camera with spatial filtering of the light for measuring the spectral reflectance factor and the spectral radiance of the objects of a scene

Spatial filtering of visible light in a spectrophotometric camera fo art work imaging

The preservation and reproduction of a still artwork needs the knowledge of its spectral reflectance, obtainable in laboratory by spectrophotometric scanners. This work proposes the design of a miniaturized spectrophotometric camera with spatial filtering of the light for measuring the spectral reflectance factor and the spectral radiance of the objects of a scene